1. Field of the Invention
The present invention relates to a sheet cutter for cutting a sheet, for example, a paper strip, thin film, cloth or the like that is adapted for image-formation.
2. Description of the Related Art
In an ordinary thermal-transfer type image-forming apparatus in which an image exposed on a photosensitive material is thermally transferred onto an image-receiving sheet, the photosensitive material is firstly unwound and pulled out by a certain length from a magazine, and thereafter a piece or sheet of photosensitive material is cut off therefrom. The sheet-form piece of photosensitive material is then conveyed to an exposure section.
In the exposure section, an image is exposed onto the photosensitive material. The image-exposed photosensitive material then has water applied thereto, and is thereafter conveyed to a transfer section. In the transfer section, the photosensitive material is overlapped with the image-receiving sheet, wound together wit h the image-receiving sheet around a heating drum, and pressed onto the heating drum by an endless belt for a predetermined length of time, so that the image on the photosensitive material is thermally transferred to the image-receiving sheet.
The image-receiving sheet is accommodated in a magazine in a coiled state. After a predetermined length of the image-receiving sheet has been unwound, a desired length of the image-receiving sheet is cut off by a sheet cutter 92 for cutting the image-receiving sheet, as shown in FIGS. 7 and 8. The cut-off image-receiving sheet is then conveyed to a transfer section.
The sheet cutter 92 features a rotary blade 98 and a fixed blade 94 with an elongated plate shape. When the rotary blade 98 is moved along the fixed blade 94 while rotating, an image-receiving sheet P which is conveyed and is situated over the fixed blade 94 is cut by an engaging portion between the rotary blade 98 and the fixed blade 94.
In the structure of this sheet cutter 92, if there was not a receiving member 100 for supporting the cut-off portion or piece of the image-receiving sheet P during cutting, burrs K and warp would inevitably be generated at an edge of the piece of the image-receiving sheet P, as shown in FIG. 9. Thus, when the sheet piece was overlapped with a photosensitive material, a small clearance C would be generated therebetween due to the burrs and warp, as shown in FIG. 10, which might cause a poor picture e.g., a so-called xe2x80x9cwhite clarityxe2x80x9d.
In actuality, the real receiving member 100 needs to have a substantial length so as to correspond to the long moving length of the fixed blade, because the receiving member 100 must be layed along the fixed blade, thereby increasing the cost of manufacture. Further, relative positioning between the rotary blade 98 and the receiving member 100 must be accurate all along the moving length. Consequently, assembly costs are increased.
In light of the above-mentioned fact, an object of the present invention is to provide a labor-saving and compact sheet cutter.
Another object of the present invention is to provide a sheet cutter in which relative positioning between a rotary blade and a receiving member during a cutting process may be precisely and properly ensured.
A further object of the present invention is to provide a sheet cutter which is capable of avoiding generation of burrs and warp at a sheet edge of a piece of an image-receiving sheet that is cut off.
A still further object of the present invention is to provide an image-forming apparatus having an improved sheet cutter.
According to the present invention, there is provided a sheet cutter for cutting a sheet piece from a sheet by shearing, the sheet cutter having: a fixed blade; a movable blade which is movable along the fixed blade; and a receiving element which receives the sheet piece that is cut off from the sheet, the receiving element being structured so as to be movable together with the movable blade.
According to the present invention, there is further provided a sheet cutter for cutting a sheet piece from a sheet by shearing, the sheet cutter having: a fixed blade; a movable blade which is movable along the fixed blade; and a receiving element which receives the sheet piece that is cut off from the sheet, the receiving element being structured so as to be translationally movable along a direction substantially perpendicular to a moving direction of the movable blade.
According to the present invention, there is yet further provided an image-forming apparatus having: a recording unit for recording an image onto a photosensitive material; a sheet cutter for cutting a piece of sheet from an elongated sheet; and a transfer unit for transferring the image recorded on the photosensitive material onto the piece of sheet. This sheet cutter includes a fixed blade, a movable blade which is movable along the fixed blade, and a receiving element that receives the piece of sheet which is cut off from the sheet, the receiving element being structured so as to be movable together with the movable blade.
The foregoing and other objects, features and advantages of the present invention will be apparent from the following description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.